<format>: Guard one use of _MSVC_EXECUTION_CHARACTER_SET

[cpplearner]

This allows EDG to parse <format> when __cpp_lib_concepts is defined. (__cpp_lib_concepts must be defined in order for <format> to work.)

Currently, __cpp_lib_concepts is not defined when the compiler is EDG, but I expect this to change soon.

STL/stl/inc/yvals_core.h

Lines 1704 to 1710 in f362f7d

	#if !defined(__EDG__) || defined(__INTELLISENSE__) // TRANSITION, GH-395
	#if _HAS_CXX23 // TRANSITION, GH-395 - move down to "macros with language mode sensitivity" section
	#define __cpp_lib_concepts 202207L // P2404R3 Move-Only Types For Comparison Concepts
	#else // ^^^ C++23 / C++20 vvv
	#define __cpp_lib_concepts 202002L // P1964R2 Replacing boolean With boolean-testable
	#endif // C++20
	#endif // !defined(__EDG__) || defined(__INTELLISENSE__)

[StephanTLavavej]

Thanks, I think we only need one maintainer approval here.

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

Thanks for scouting ahead and improving how EDG handles the STL's concepts-enabled code! 🥾 🏞️ 🎉